I'll strip the outer insulation and see what the deal is. Also, I thought Pin 1 is supposed to be data, not ground?
Must be the break in the cable mucking up my tests, but I tested from each pin in the mini-DIN (with this graph for reference) to the pins on the PCB and found the opposite of your notes.
Mini-DIN Casing = Black
Pin 1, Data = Black
Pin 3, 5v Power = Orange